from how stuff works
myths about the brain
Discovery Health "Subliminal Learning"
7: You Can Learn Through Subliminal Messages
The concept of subliminal messages feeds into our suspicions about what the government, big corporations and media are really trying to tell us. A subliminal message (meaning, below "limen," or our conscious perception threshold) is a message embedded into images or sound meant to penetrate into our subconscious and influence our behavior. The first person to coin the term was James Vicary, a market researcher. In 1957, Vicary stated that he inserted messages into a showing of a movie in New Jersey. The messages, which flashed for 1/3000th of a second, told moviegoers to drink Coca-Cola and eat popcorn.
According to Vicary, Coke sales in the theater increased by more than 18 percent and popcorn sales by more than 57 percent, proving that his subliminal messages worked. Books published in the late 1950s and early 1970s outlined how advertisers could use techniques like Vicary's to convince consumers to buy their products. Some radio and TV commercials included subliminal messages, but many networks and professional associations banned them. In 1974, the FCC banned the use of subliminal advertising.
But did the messages work? Turns out, Vicary actually lied about the results of his study. Subsequent studies, including one which flashed the message "Call now" during a broadcast on a Canadian TV station, had no effect on viewers. The infamous 1990s Judas Priest trial, in which the families of two boys who committed suicide claimed that a song told the boys to do it, ended with the judge stating that there was no scientific evidence in their favor. Yet some people still claim that music, as well as advertisements, contains hidden messages.
So listening to those self-help tapes while you sleep probably can't hurt you, but they aren't likely to help you quit smoking, either.
and the biggest myth,usually cited by people who insist they are pshycic or believe such persons exist 
1: You Only Use 10 Percent of Your Brain
We've often been told that we only use about 10 percent of our brains. Famous people such as Albert Einstein and Margaret Mead have been quoted as stating a variation of it. This myth is probably one of the most well-known myths about the brain, in part because it's been publicized in the media for what seems like forever. Where did it come from? Many sources point to an American psychologist of the early 1900s named William James, who said that "the average person rarely achieves but a small portion of his or her potential" [source: AARP]. Somehow, that was converted into only using 10 percent of our brain.
This seems really puzzling at first glance. Why would we have the biggest brain in proportion to our bodies of any animal (as discussed in the sixth myth in our list) if we didn't actually use all of it? Many people have jumped on the idea, writing books and selling products that claim to harness the power of the other 90 percent. Believers in psychic abilities such as ESP point to it as proof, saying that people with these abilities have tapped into the rest of their brains.
Here's the thing, though; it's not really true. In addition to those 100 billion neurons, the brain is also full of other types of cells that are continually in use. We can become disabled from damage to just small areas of the brain depending on where it's located, so there's no way that we could function with only 10 percent of our brain in use.
Brain scans have shown that no matter what we're doing, our brains are always active. Some areas are more active at any one time than others, but unless we have brain damage, there is no one part of the brain that is absolutely not functioning. Here's an example. If you're sitting at a table and eating a sandwich, you're not actively using your feet. You're concentrating on bringing the sandwich to your mouth, chewing and swallowing it. But that doesn't mean that your feet aren't working -- there's still activity in them, such as blood flow, even when you're not actually moving them
